Fix sporadic segfaults in tasking tests.
Fix sporadic segfaults in tasking tests.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D35535


git-svn-id: f99161ee8ccfe2101cbe1bdda2220bce2ed25485@308298 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/openmp,llvm-mirror/openmp,llvm-mirror/openmp,llvm-mirror/openmp,llvm-mirror/openmp